This invention is in the field of biological research and drug discovery, specifically in cell-based assays.
Tissue culture of plant and animal cells in vitro allows researchers to identify critical chemical factors affecting the functions of cells, such as spreading, morphology, motility, and differentiation. Currently, majority of tissue culture experiments are performed on flat surfaces of plastic or glass vessels. The measurements are obtained from large groups of cells without the ability to identify, to monitor and to measure an individual cell. The results are an average of the entire cell population.
In order to monitor and to measure a single cell, a tissue culture vessel is typically placed on a microscope stage. The tissue culture vessels remains on the stage until the measurement is complete, while the duration of the experiment may be from hours to days. The throughput of this method is extremely low. To increase the throughput, instruments with high precision motion control are designed to locate the tissue culture vessel to the same location repeatedly. Between each measurement, the tissue culture vessel is placed in an incubator while the microscope performs other measurements. Instruments of this type are typically complex and expensive.
Another method used to identify individual cells is using tissue culture vessels with embedded patterns as identification marks. U.S. Pat. No. 4,415,405 described a method for engraving a grid pattern on microscope slides and slips. The disclosed method employs a photographic technique to create a grid pattern image in a photo-resist coating on the slide or slip. Development of photo-resist and subsequent etching of glass produce the engraved slide or slip. A limitation of this technique is that engraved slides and slips are expensive to make with this method. In addition, the glass surface also limits the kind of cells that can be grown, since some cells do not grow on glass.
One objective of the current invention is to provide a tissue culture vessel that is capable of direct identification and measurement of individual cell activities, and also the tissue culture vessel can be fabricated with an inexpensive method.
Creation of microscopic features in plastic material from a molding surface has been described in the prior art. Process of making optical disks with microscopic features using photo-polymerizable materials is disclosed in U.S. Pat. No. 4,374,077. Microstructure-bearing composite plastic articles and method of making said articles are disclosed in U.S. Pat. No. 5,175,030. Grid lines directly molded onto the plastic for cell counting is disclosed in U.S. Pat. No. 4,997,266. U.S. patent application Ser. No. 10/760,000 disclosed a novel cell counting device with embedded grid lines.